The present invention relates to an improvement in a cone lock which is related to the art of loading and fixedly fastening containers.
For example, in the case where a number of containers are loaded on a ship, when they are merely stacked on the ship, there possibly occurs a dislocation of loads due to rolling of the ship or the like on sail. Therefore, various metal fittings for the purpose of connection and fixedly fastening are interposed between the floor surface and containers in a first layer, and between containers stacked one upon another. The present inventor has previously proposed a cone lock used as one kind of the metal fittings, as shown in the drawings of Japanese Utility Model Application Laid-Open No. 2580/1987 (Japanese Utility Model Application No. 93025/1985) publication. This proposed cone lock generally has an arrangement as will be described below.
That is, as shown in FIGS. 23 to 27, a shaft 53 is longitudinally extended into a casing 51 provided with a horizontally spread support board 52, and a pair of cones 54 and 55 are fixedly mounted on upper and lower ends of the shaft 53, said shaft 53 and both cones 54 and 55 being rotated by the pivotal movement of an operating lever 56 of which base end is secured to the shaft 53. These cones 54 and 55 are inserted into engaging holes 73 and 75 of cone sockets (see FIGS. 19 to 21 later described) mounted at corners of the container, and have a planar rectangular shape so that the cones may be engaged with the cone sockets by the rotation caused by the operation of the lever 56 after being inserted. The lever 56 is normally maintained at 45 degrees counterclockwise relative to a center line 51a of the casing 51 (When the cone lock is mounted for use, the center line 51a is placed in registration with center lines 73a and 75a extending lengthwise of the engaging holes 73 and 75 to serve as a reference for determining the relative position between the cones 54 and 55 and the engaging holes 73 and 75.) by means of a spring 57 held between the support board 52 and the shaft 53 being biased. At that time, both the upper and lower cones 54 and 55 are placed in their normal locked position with respect to the respective engaging holes 73 and 75 as shown in FIG. 26, which state is a basic attitude, and under this state, the lever 56 is operated to rotate the cones 54 and 55. The lower cone 55 is formed with torsional bevels 58 and 58 which come into contact with the edge of the engaging hole 73 to automatically rotate the cone 55 so as to be inserted into the engaging hole 73. So the lower cone 55 is automatically rotated while being guided by the bevels 58 and 58 other than the operation of the lever 56. The prior application disclosed in the aforementioned publication is intended to enhance to the working efficiency and safety of the work of fixedly fastening containers by automatically rotating the cone 55 with the provision of the bevels 58 and 58. However, as a result of a further research, there is found a further improvement as will be discussed below.
In an actual situation of fixedly fastening containers utilizing the aforesaid cone lock, the upper cone 54 is first engaged with the lower engaging hole 73 of the cone socket 72 at the lower corner of the container in the upper layer 71A pulled up by a crane (For the container 71A, see FIGS. 19 to 21 later described. Where the floor surface and the container 71B in the first layer are connected, the container 71B in the first layer is indicated, in which case, avoidance of work at a high level is not demanded, the cone lock is turned upside down and first can be mounted on the floor surface.); the cone lock being suspended on the container 71A is transferred to the container 71B in the lower layer and lowered on the cone socket 75 at the upper corner. As previously mentioned, the lower cone 55 is provided with the guide bevels 58 and 58 and therefore, the cone 55 is automatically rotated, and inserted into and engaged with the engaging hole 75. At the time when the upper cone 54 is first mounted on the upper layer side, the end of the operating lever 56 is made possible for operation after mounting, and therefore it assumes an attitude to be projected laterally and outwardly from the side of the cone socket 72 or from the side of the container 71A body face to the first-mentioned side. Therefore, when the end of the lever 56 is erroneously brought into contact with the lower layer container 71B during the transfer of the upper layer container 71A with the cone lock first attached thereto onto the lower layer container 71B by the crane, the lever 56 freely swings depending upon the direction thereof, as a result of which the upper cone 54 is possibly disengaged from the engaging hole 73 to allow the cone lock to fall. This lowers the working efficiency, gives rise to a breakage of the cone lock due to the shock caused by such falling or leads to a possible unexpected personal accident. In this case, the spring 57 adapted to urge the operating lever 56 so as to maintain the latter in a normal state acts, to be sure, in a direction of impeding the free pivotal movement thereof, but the spring 57 merely has a force so weak that is enough to swing the lever 56 by hand, and therefore cannot restrain the pivotal movement of the lever 56.
Furthermore, in the unloading work, the aforesaid cone lock is suspended on the upper layer container 71A which is released from engagement with the lower layer container 71B and pulled up by the crane. The lever 56 is operated prior to the pull-up in order to disengage the lower cone 55 from the engaging hole 75 of the socket 74 in the lower layer container 71B. In this operation, the lever 56 is pivotally moved approximately 75 degrees clockwise from the normal attitude thereof but sometimes, both the upper and lower cones 54 and 55 have their open-rotating direction from the normal state set to the same direction and both the cones 54 and 55 are superposed in plane to simultaneously assue the open position with respect to the upper and lower engaging holes 73 and 75 (see FIG. 27). Therefore, if the pull-up by the crane is started before the operation of the pivotal movement of the lever 56 is completely finished, both the upper and lower cones 54 and 55 become simultaneously disengaged despite only the lower cone 55 is originally disengaged, and consequently, the cone lock is sometimes left on the lower layer container 71B without being suspended on the upper layer container 71A.